1. Field of the Invention
The present invention is directed generally to a planar optical display, and, more particularly, to a small inlet optical panel and a method of making a small inlet optical panel.
2. Description of the Background
It is known in the art to form an optical panel from a plurality of stacked waveguides. The waveguides collectively define an inlet face at one end of the waveguides and an outlet face at an opposite end. The outlet face may be disposed obliquely with the inlet face. The outlet face may form an small acute face angle with the longitudinal axes of the waveguides, thus allowing the height of the screen to be substantially larger than the depth or thickness of the panel. The panel inlet face generally extends the fill width of the panel correspondent to the width of the outlet face, but is very narrow due to the thinness of the panel. For example, where an inlet face has a width of 133 cm, the corresponding length in the prior art would be 2.54 cm.
The narrow inlet face necessitates the use of a complex light projection system for distributing and focusing the image light across the full width and depth of the panel, thereby allowing for accurate display on the outlet face. This complex light projection system increases the complexity and cost of the overall system, and increases the space requirements of the display panel.
Therefore, the need exists for a waveguide optical panel having an aperture inlet which allows for simplification of light projection and focusing at the inlet, without a loss of image resolution at the outlet face.
The present invention is directed to a small inlet optical panel, which includes a first plurality of stacked optical waveguides which forms an outlet face body with an outlet face, which includes a second plurality of stacked optical waveguides which forms an inlet face body with an inlet face, and an optical coupling element connected to the first plurality and to the second plurality, wherein the optical coupling element redirects light along a parallel axis of the inlet face to a parallel axis of the outlet face. In the preferred embodiment of the present invention, the inlet face is disposed obliquely with and askew from the outlet face.
The present invention is also directed to a method of making a small inlet optical panel which includes individually coating a plurality of glass sheets in a substance having an index of refraction lower than that of the glass sheets, stacking the plurality of coated glass sheets, wherein each coated glass sheet is fastened to an adjoining glass sheet using an adhesive, applying pressure to the stack, curing the adhesive, cutting the stack to form an outlet face body having a first wedge shape with an outlet face thereon, repeating the individually coating, the stacking, the applying and the curing to form a second stack, cutting the second stack to form an inlet face body having a second wedge shape correspondent to the first wedge shape and having an inlet face thereon, and joining together the inlet face body and the outlet face body at an optical coupling element, wherein the outlet face is disposed askew from the inlet face, for redirecting light incident into the inlet face body to a direction incident into the outlet face body.
The present invention solves difficulties encountered in the prior art by providing a waveguide optical panel having a small aperture inlet, which allows for simplification of light projection and focusing at the inlet, without a loss of image resolution at the outlet face.